Test Driven Development Background

What is Test Driven Development?

You write a test first before you write the code. You use the tests to drive the design.

It uses one of the XP concepts : Test-First programming to achieve another XP concepts : Emergent Design.

In Emergent Design you start delivering functionality that has business value and let the design emerge. You will deliver functionality A with unit tests and then build functionality B. Then refactor to reduce duplication due to A and B and let the design emerge.

Origins of Test Driven Development

Extreme Programming Explained - Embrace Change by Kent Beck
Refactoring by Martin Fowler

Why TDD ?

- It results in simple design and minimal code.
- Higher quality code due to less defects
- Lower cost to maintain
- Brings fun back to programming

When is TDD not applicable?

- Multi-threading
- Asynchronous Code
- Prototyping
- Exploratory work such as Architectural spike
- Checking the structure of user interfaces such as HTML
- Testing usability of user interfaces

What makes TDD difficult

- Doing TDD without pair programming. TDD and pair programming are complementary.
- Existing code base with no tests

Flog Scoring

Score of    Means
0-10        Awesome
11-20       Good enough
21-40       Might need refactoring
41-60       Possible to justify
61-100      Danger
100-200     Whoop, whoop, whoop
200 +       Someone please think of the children

`raise_if_continuation_resulted_in_a_channel_error!': PRECONDITION_FAILED - parameters for queue 'hello' in vhost '/' not equivalent (Bunny::PreconditionFailed)

This error happens when you have a queue that is not durable and you are doing something to assume that it is durable. Change the name of the queue to a new name and make it durable to fix this error.

How to customize Rails 404, 422, 500 pages that is compatible with Exception Notifier Plugin

1. Add :
            config.exceptions_app = self.routes

to application.rb.

2. Add routes for error pages :

  match '/404', :to => 'errors#not_found'

  match '/422', :to => 'errors#server_error'

  match '/500', :to => 'errors#server_error'

3. Create a errors controller:

     rails g controller errors not_found server_error

4. Implement the actions :

class ErrorsController < ApplicationController

  def not_found

    render :status => 404, :formats => [:html]

  end

  def server_error

    render :status => 500, :formats => [:html]

  end

end

5. Customize the views, not_found.html.erb and server_error.html.erb.

Updates were rejected because a pushed branch tip is behind its remote

If you are working on a branch and it gives you this error message when you do a git push, you need to run:
git pull origin master

and now the git push will work. This happens when the master changes and you have not updated the local copy with the changes in the remote master branch.

You are using .rvmrc, it requires trusting, it is slower and it is not compatible with other ruby managers, you can switch to .ruby-version using rvm rvmrc to [.]ruby-version or ignore this warnings with rvm rvmrc warning ignore

rvm rvmrc to .ruby-version

Clearing Stuck Delayed Jobs

Delayed job had completed its work, for some reason it was still stuck in the queue. To remove it from the queue, on the server run the commands:

Step 1 :

$ RAILS_ENV=production script/delayed_job stop

This will stop the delayed_job process.

Step 2 :

$ pgrep -f delayed_job

This will return no result, therefore confirming that the delayed_job process has been stopped.

Step 3:

Go to rails console in production and run :

> job = Delayed::Job.count
   (0.3ms)  SELECT COUNT(*) FROM `delayed_jobs`
=> 1

> job = Delayed::Job.first
  Delayed::Backend::ActiveRecord::Job Load (0.5ms)  SELECT `delayed_jobs`.* FROM `delayed_jobs` LIMIT 1
=> #
> job.delete

Disable Edit and Delete in Rails Admin

Add the following code to rails_admin.rb:


  RailsAdmin.config do |config|
    config.actions do
      # root actions
      dashboard                     # mandatory
      # collection actions
      index                         # mandatory
      new
      export
      history_index
      # member actions
      show
      history_show
      show_in_app
    end
  end

As you can see from above, there is no edit or delete actions defined. Now you will not be able to edit or delete the models when you are logged in as admin.

Due to Kaminari and Will Paginate conflict in Rails Admin, to fix this add the following code to kaminari.rb in config/initializers:

config.page_method_name = :per_page_kaminari

How to find ruby gems

1. Look at the Gemfile.lock and see the dependencies of a gem. Search in github for each gem in the dependency tree to learn more about the gem. You can also use the gem command :
    gem dependency gem_name to get a list of dependencies of a gem. For instance, running :
 
    $ gem dependency capistrano

   Gives the following output:

Gem capistrano-2.15.5
  highline (>= 0)
  mocha (= 0.9.12, development)
  net-scp (>= 1.0.0)
  net-sftp (>= 2.0.0)
  net-ssh (>= 2.0.14)
  net-ssh-gateway (>= 1.1.0)

2. Follow the Rails Core Team members Twitter feed.
3. Talk to other developers and ask what gems they have used in their projects.
4. Subscribe to Ruby podcasts, blogs.

I was working on a Rails project that was having a giant if-else statements to recognize the mime-types of a given file for uploading to Amazon S3. I was looking at Gemfile.lock and used tip #1 above to find the mime-types and read more about the gem on github. I was able to replace my custom mime-type recognition code with the mime-types gem. If you run:

$ gem dependency mime-types

you will see only development dependencies on other gems, there are no runtime dependency on any other gems. This gem is self-contained and is a good unit of reuse.

It's like using small Unix utility to compose and solve many different problems. The only dependency it might have is that it works only on certain versions of Ruby.

Things to Consider When Evaluating Gems

1. Simplicity vs Flexibility

     There is a trade-off between simplicity and flexibility. For instance for file uploading you could use many gems like fog, carrierwave etc and create lot dependencies in your code that provides ease of switching between libraries - flexibility. But it complicates your codebase and simplicity is lost. You will also have more work during upgrade of your project because of these dependencies.

2. Usefulness

     Can I write this by myself in a simpler way that is easier to manage? Read the source code of the gem to make your own decision about reuse or develop on your own.

3. Support and Maintenance

•     Is there any critical bugs that is not being addressed by anyone? 
•     Is the source code easy to read and modify for your needs? 
•     Are the developers active and keep up with upgrading the gem as new Ruby versions are released?

bundler not installing gems in the current gemset

To force bundler install gems for the current gemset run:

GEM_PATH=$GEM_HOME bundle install

List gems for current gemset in rvm

$ GEM_PATH=$GEM_HOME gem list

PATH is not properly set up RVM

Run :
rvm get head

undefined method your_method for Syck::Object Delayed job

Add :


require 'yaml'
YAML::ENGINE.yamler = 'syck'

lines to the top of application.rb.

Three Rules of TDD

Notes from Bob Martin's screencast:

1. Write the test first.
2. Write only enough of a test to demonstrate a failure.
3. Write only enough of production code to pass the test.

Authlogic::Session::Activation::NotActivatedError: You must activate the Authlogic::Session::Base.controller with a controller object before creating objects

In rails console run :

 Authlogic::Session::Base.controller = Authlogic::ControllerAdapters::RailsAdapter.new(self)

Reference

iomega external drive is not showing up on Mac OS

1. In a terminal run : sudo chflags nohidden /Volumes/*

Since I did not know the name of my iomega drive I used the wildcard * instead of the name for the external drive.

2. Unplug the power to the external drive and connect it back to your Mac.

It should work now.

How to Setup Amazon Cloud Front in Rails 3.2 app

I bought my domain at namecheap.com. It is hosted at Linode.

Step 1 : I used Linode control panel to create a CNAME. It looks like this:

CNAME Records
Hostname Aliases to TTL
cdn amazon-provided-id.cloudfront.net Default
www clickplan.net Default

Step 2 : Go to Amazon Cloud Front and setup a CDN distribution. I followed the instructions from this blog: http://happybearsoftware.com/use-cloudfront-and-the-rails-asset-pipeline-to-speed-up-your-app.html

Note that you should also provide alternate domain name. In my case it was cdn.clickplan.net.

Step 3 : In production.rb add :

  config.action_controller.asset_host = "amazon-provided-id.cloudfront.net"

You can also setup a CNAME like cdn.yourdomain.com to point to amazon-provided-id.cloudfront.net. I am using https for the entire site. Since I did not have wildcard SSL certificate, it did not work so I am using https://amazon-provided-id.cloudfront.net for now. Amazon also has a documentation that shows how to use SSL with your cname. If you have issues, make sure you clear all the history in the browser and hit the URL to see if you can view the css and javascript.

How to stop Rails 3.2 from including javascript twice

Make sure the development.rb has :


  config.assets.debug = false

How to control the order of css file inclusion in Rails 3.2 asset pipeline?

In your application.css remove the require_tree .
Then add the css files one by one in the order you would like it to be included in the html. Like this:

*= require_self
*= require 'form'
*= require 'layout-fix'

and so on. Just leave the require_self as it is. For a detailed explanation: RAILS ASSET PIPELINE HANDLING OF CSS & JS 

NoMethodError: undefined method `y' for main:Object

If you want to use the y method to inspect an object in yaml format. Whenever you bring up rails console in development, you can inspect any object.  Just add the following line to your development.rb:

YAML::ENGINE.yamler = 'syck'

How to print text in green in Ruby

text = "This is a test"
irb > print "\033[32m#{text}\033[0m"
This will print the text in green.

NoMethodError: undefined method `buckets' for :AWS::Core::Configuration

Resolution: Use the constructor version of S3 : s3 = AWS::S3.new('your credentials')

ignoring config/database.yml

If you already have the config/database.yml file in the repo and you want to ignore it. Follow these steps:

1. Add : config/database.yml to .gitignore file.
2. Rename database.yml to database.yml.sample
3. Check in the changes.
4. Now git will ignore the database.yml that you create in your project.

Keeping Security Credentials Out of Source Code Repository

Moonshine is supposed to keep the file in the shared folder and symlink it to the file under current project folder just by adding one line to the config/moonshine.yml

:shared_config
  - config/amazon_s3.yml

For some reason it created the symlink but it did not upload the file. I had to manually do it by :

cap shared_config:upload

on my laptop. On initial setup it actually worked for database.yml. I think it is because of cap deploy:setup command. Remember to add the config file to the .gitignore file so that it does not get checked into the repo.

Consuming Webservices deployed on Google App Engine from Rails

Google App Engine is very attractive for exposing services that needs to be up and running 24x7 and scale automatically based on demand. Rails apps can consume RESTful services developed using Google Cloud Endpoints. Even though Google Cloud Endpoints is experimental,  platform developers will find very compelling. Any platform that can make a http request can consume the services.

1. Using OAuth 2.0 for Server to Server Applications
   
2. Google APIs Client Library for Ruby
Here is the github repo :  https://github.com/google/google-api-ruby-client

3. Code to Cloud in under 45 minutes

4. Slides from 18 to 34 from Pycon2013

5. Google Cloud End Points sample project
 
6. Python End Points

7. OReilly Webcast : Python for Google App Engine

The absolute uri: http://www.oracle.com/technetwork/java/javaee/jsp/index.html cannot be resolved in either web.xml or the jar files deployed with this application

To get the guestbook.jsp App Engine example working replace the tag library fn as follows:

<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>

Error: Cannot find module 'npmlog'

1. npm install -g yo grunt-cli bower gives the error:

Fix : sudo curl https://npmjs.org/install.sh | sh

How to upgrade Node.js

1. Check the version :  $node --version
   output will be like : n@0.9.3 /usr/lib/node_modules/n

2. To upgrade, run : $n 0.9.3
where, 0.9.3 is from the output of step 1.

Open a new terminal and type: $node --version
You should see the upgraded version.
   

SQLite3::BusyException: database is locked: ROLLBACK TO SAVEPOINT active_record_1

Caused SQLite3 to lock due to bug in a test. To fix:

1. ps -a | grep ruby
2. kill -s 9 12345

12345 is the process id that is the zombie rspec process.

WARNING: Nokogiri was built against LibXML version 2.8.0, but has dynamically loaded 2.9.0

Copied from https://github.com/sparklemotion/nokogiri/issues/742

Moved gem 'nokogiri' in the Gemfile to the top (just below gem 'rails') then:

brew uninstall libxml2
gem uninstall nokogiri
gem install nokogiri

AbstractController::ActionNotFound:

       Could not find devise mapping for path "/users/sign_in?user%5Bemail%5D=bparanj%40gmail.com&user%5Bpassword%5D=secret".
       This may happen for two reasons:
     
       1) You forgot to wrap your route inside the scope block. For example:
     
         devise_scope :user do
           get "/some/route" => "some_devise_controller"
         end
     
       2) You are testing a Devise controller bypassing the router.
          If so, you can explicitly tell Devise which mapping to use:
     
          @request.env["devise.mapping"] = Devise.mappings[:user]

Solution:


  before :each do
    request.env['devise.mapping'] = Devise.mappings[:user]
  end

How to select the non highlighted button in the popup window on Mac OS

Go to Preferences -> Keyboard. At the bottom, turn on "All controls" under "Full Keyboard Access". Hit space to activate the secondary button.

GitHub Error – You don’t exist, go away!

At the terminal run:

dscacheutil -flushcache

How to checkout a specific tag from a Git repo

git checkout tag-name

How to Setup Development Environment to Contribute to Rails

Use the Rails Dev Box available at : https://github.com/rails/rails-dev-box

How to store array in mysql database in a Rails project

1. The column type should be text
2. serialize the column. In the active record class : serialize :your_field
3. Book.new(:your_field => [1,2])

How to limit svn log output to a given number of entries

Use limit option: svn log -l 5

Correction to Example in Ruby Programming Language

In Ruby 2.0, I had to make changes to the given code in the book:

birthyear = 1975

generation = case birthyear
    when 1946..1963 then "Baby Boomer"
    when 1964..1976
      "Generation X"
    when 1978..2000
      "Generation Y"
    else nil
    end

p generation

How to use VCR, Webmock with RSpec

1. Add the gems to the Gemfile under test group:
gem "webmock"
gem "vcr"

2. bundle

3. require 'vcr' as the first line in spec_helper.rb

4. Add

VCR.configure do |c|
  c.cassette_library_dir = 'spec/fixtures/cassettes'
  c.hook_into :webmock
  c.ignore_localhost = false
  c.allow_http_connections_when_no_cassette = true
end

inside the configure block.

5. Add WebMock.allow_net_connect! in the before block in the specs.
6. Wrap your network calls using :
       VCR.use_cassette do
              controller code that accesses network goes here
        end

Two different ways to execute a block

It is familiar that you will see yield being used when the block is anonymous and block.call being used when the block is explicit in the list of parameters for the method. Actually, you can use yield even when the block is explicitly passed to the method:

def foo(&block)
  yield
  block.call
end

foo { puts 'hi hey again' }

Setting two spaces as the default in Sublime Text 2

{
    "tab_size": 2,
    "translate_tabs_to_spaces": true
}

Save this in the Preferences -> Settings - Default file.

Installing Guest Additions on Ubuntu 12.04

1. sudo apt-get install virtualbox-guest-additions-iso
2. Boot the guest OS inside Virtualbox
3. In the virtual box menu, use Devices -> Install Guest Additions.

Reference: ubuntuforums.org

uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)

This happens when creating a new project in Rails 2.3.8 if the Ruby gems version is 1.8.24.
Solution:

gem update --system 1.5.3

Now, rails blog will create a new project. 

program rails is not installed ubuntu rvm rails 2.3.8

1. Type : gem env, look at the  EXECUTABLE DIRECTORY value

2. Add the path to that directory to ~/.bashrc:
PATH="${PATH}:/home/your-user-name/.rvm/gems/ruby-1.8.7-p299/bin"


3. Open a new terminal

4. Type : rails -v



You will now see that rails command is recognized.

How to configure Sublime Text 2 to use Ruby 2.0 using RVM

{ "env":{ "PATH":"${HOME}/.rvm/bin:${PATH}" }, "cmd": ["rvm-auto-ruby", "$file"], "file_regex": "^(...*?):([0-9]*):?([0-9]*)", "selector": "source.ruby" }

Copy this file to your rvm.sublime.build file.

For more info: Sublime Text 2 Integration With RVM and Rspec: Take Number 2

How to configure rspec to test controller macros

Include the line:
  config.include OnboardingControllerMacros, :type => :controller

in spec_helper.rb

Readline was unable to be required, if you need completion or history install readline then reinstall the ruby.

This happens on Ubuntu 12 when installing Ruby 2.0 using RVM. To fix this follow the instructions below:

If you're using Ubuntu 12.04, DO NOT pkg install readline, with or without --skip-autoreconf. After you've done that, either readline or zlib will be broken no matter what combination of switches you give to rvm install ruby-2.0.0-p0 . To get it to work, do the apt-get install that rvm requirements tells you to do, do a rvm pkg uninstall readline and then do a simple rvm remove ruby-2.0.0-p0; rvm install ruby-2.0.0-p0 Now the irb should work fine without any warnings.   http://stackoverflow.com/questions/8176076/how-to-get-readline-support-in-irb-using-rvm-on-ubuntu-11-10

iPhone 5 cord stuck in USB Port

You can easily remove your iPhone 5 cable stuck in USB port by using either your shirt collar stays or a toothpick. Just stick it inside the USB port, sitting on top of the cable and pull them together.

Accessing Git Repository on Github

Problem:
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Solution:

Password Caching (Explains how to use https to access repository and cache password so you don't get annoying password prompt whenever you have to access the github repo)

1. curl -s -O \

  http://github-media-downloads.s3.amazonaws.com/osx/git-credential-osxkeychain

chmod u+x git-credential-osxkeychainsudo mv git-credential-osxkeychain `dirname \`which git\``
git config --global credential.helper osxkeychain

Using Bundler Outside Rails

1. bundle init
2. Open Gemfile and add your gems : gem 'highline'
3. bundle

Bundler without Rails

Using Phusion Passenger as a Rails Server on Mac OS X 10.7.5

Software used : RVM Passenger 3.0 on Mac OS X 10.7.5

1. rvm use 1.9.3
2. gem install passenger
3. rvm get head
4. rvm reload
5. rvm repair all
6. passenger-install-apache2-module

Could not find gem 'activerecord-sqlite3-adapter (>= 0) ruby' in the gems available on this machine.

Instead of

gem install activerecord-sqlite3-adapter

run

gem install sqlite3

Archimedes and the Internet

If Archimedes was born in this era, he would say:

Give me a single email account, and a website, and I will move the Internet.

Playing with URL Helpers in Rails 3.2 Console

 :001 > Rails.application.routes
 => # 
 :002 > Rails.application.routes.url_helpers
 => # 
 :003 > Rails.application.routes.url_helpers.permissions_get_access_token_url
ArgumentError: Missing host to link to! Please provide the :host parameter, set default_url_options[:host], or set :only_path to true
 :004 > Rails.application.routes.url_helpers.permissions_get_access_token_path
 => "/permissions/get_access_token"
 :005 > Rails.application.routes.url_helpers.permissions_get_access_token_path(:host => 'http://localhost')
 => "/permissions/get_access_token"
 :006 > Rails.application.routes.url_helpers.permissions_get_access_token_url(:host => 'http://localhost')
 => "http://http://localhost/permissions/get_access_token"
 :007 > Rails.application.routes.url_helpers.permissions_get_access_token_url(:host => 'localhost')
 => "http://localhost/permissions/get_access_token"
 :008 > Rails.application.routes.url_helpers.permissions_get_access_token_url(:host => 'localhost:3000')
 => "http://localhost:3000/permissions/get_access_token"

 or

  :001 > include ActionDispatch::Routing
  => Object
  :002 > include Rails.application.routes.url_helpers
  => Object
  :003 > permissions_path
  => "/permissions"
  :004 > permissions_url
 ArgumentError: Missing host to link to! Please provide the :host parameter, set default_url_options[:host], or set :only_path to true
  from /Users/bparanj/.r

Reference:
Recognizing URL Helpers

protocol version mismatch (client 7, server 6) tmux

ps aux | grep tmux

Look at the second column for the process id. Then run : kill process-id-for-tmux

SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed

1. Install GCC Installer https://github.com/kennethreitz/osx-gcc-installer
2.

rvm remove 1.9.3
brew install openssl
rvm install 1.9.3 --with-openssl-dir=`brew --prefix openssl`

# Install openssl
echo "Install openssl..."
brew install openssl
brew link openssl
# download cert.pem file for openssl
cd /usr/local/etc/openssl/certs/
sudo curl -O http://curl.haxx.se/ca/cacert.pem
sudo mv cacert.pem cert.pem
cd -
echo "
# cert.pem file for openssl 
export SSL_CERT_FILE=/usr/local/etc/openssl/certs/cert.pem" >> ~/.bash_profile
source ~/.bash_profile

Shell script to turn your laptop to a development machine.

PayPal Application id for Sand Box

Use APP-80W284485P519543T as the app_id

This is the same for all sandbox users and any PayPal API (Adaptive Payments, Express Checkout etc).

Convert HAML to ERB

1. rails g install haml2erb
2. Gemfile :
gem 'mixology'
3. bundle
4. Rails console : Haml2Erb.convert('.foo')

This plugin is not perfect. I had to refer HAML documentation to convert some of the lines.

no such file to load -- less Twitter Bootstrap, Rails 3.2.11

1. In Gemfile, for group :assets block, add:

        gem "less-rails"

2. Add to Gemfile (not in any block), add:

         gem 'therubyracer', :require => 'v8'

3. bundle

It will now work.

rake aborted! can't convert nil into Hash

Solution Source:

Rails 3.1, rake 0.9.2.2, add this code on config/boot.rb

require 'yaml'
YAML::ENGINE.yamler = 'syck'

Useful Tools for Testing Web API

1. RSpec HTTP : https://github.com/c42/rspec-http

response.should be_http_ok
response.should be_http_created
response.should be_http_unprocessable_entity
response.should be_http_im_a_teapot
response.should have_header('Content-Type')
response.should have_header('Content-Type' => 'application/json')
response.should have_header('Content-Type' => /json/)

2. JSON Spec : https://github.com/collectiveidea/json_spec

json_spec defines five new RSpec matchers:

be_json_eql
include_json
have_json_path
have_json_type
have_json_size

3. VCR : https://github.com/myronmarston/vcr

Screencast on VCR : http://avdi.org/devblog/2011/04/11/screencast-taping-api-interactions-with-vcr/

'too many connection resets (due to HTTP session not yet started - IOError) after

This happens when you use VCR with Webmock. There is an open bug on Webmock that is causing this problem. The fix is to either downgrade the Webmock to 1.0 version or use Fakeweb.

Using pry in test environment

Is it possible to use pry when I am running my tests? Sometimes when I am running specs for legacy code, I need a way to experiment with the existing code.

Answering my own question. Yes, it is possible. Just add binding.pry in the production code, run the specs, pry will stop at the line where you have the binding in the terminal window where you have the test running. You can also use pry-nav to use the ruby debug familiar commands step, next and continue while you debug the code.

Installing Ruby 2.0 on Mac OS 10.8.2 using RVM

1. Make sure you have the latest RVM
     rvm get head
     rvm reload

$ brew install autoconf
$ brew install automake
$ brew install libyaml

$ rvm install ruby-head

Stolen from the blog post instructions : How to install Ruby 2.0 (ruby-head) with RVM

Creating a New File in a Folder in Textmate 2

Textmate 2 does not have the quick shortcut to create a file from a selected folder. Here is a workaround:

1. Select the folder where you want the new file.
2. Hit Option+Command+N keys to create a new file.
3. Add the content and save the file. It will get saved in the selected folder.

To open a bundled gem, set $EDITOR or $BUNDLER_EDITOR

1. bundle open rails
      gives that error.
2. Add :
      export BUNDLER_EDITOR=mate
    to ~/.bash_profile

How to push branch to remote

To check-in your new branch you created locally : 1. git checkout -b your_branch 2. git push -u origin your_branch

rvm is not a function on Ubuntu 10.04

1. $ source ~/.rvm/scripts/rvm

2. $ type rvm | head -n 1

Configuring Moonshine to use Apache XSendFile for Rails 3.2

1. rails plugin install git://github.com/railsmachine/moonshine_xsendfile.git
2. In the Moonshine manifest file:

    configure :xsendfile => {:x_send_file_path => '/absolute/path/to/download/url'}

    recipe :xsendfile

   
    This will work even if you have subdirectories under the /are directory.
3. In production.rb, uncomment the line:

    config.action_dispatch.x_sendfile_header = "X-Sendfile" # for apache

4. In your controller:

      send_file '/absolute/path/to/download/url/file.pdf', type: 'application/pdf'

Rails 3.2, Factory Girl

1. Include :
 
    group :development, :test do
 gem 'factory_girl_rails'
end

in Gemfile

2. bundle install
3. create factories.rb under spec folder
4. Add the factory definitions in it :

FactoryGirl.define do
 factory :user do
   email 'elinora@zepho.com'
   password 'welcome'
   primary_paypal_email 'elinora.price@zepho.com'
 end
 # product factory with a belongs_to association for the user
 factory :product do
   name 'TDD Workbook'
   price 49.99
   user
   thanks_page 'www.zepho.com/thanks.html'
   cancel_page 'www.zepho.com/cancel.html'
   sales_page 'www.zepho.com/sales_page.html'
   download_page 'www.zepho.com/download.html'  
 end
end

In this definition I have factory for user has_many :products relationship.
5. Create a support directory and include controller_macros.rb in it:
module ControllerMacros
 def login_user
   @request.env["devise.mapping"] = Devise.mappings[:user]
   user = FactoryGirl.create(:user)
   # user.confirm! # or set a confirmed_at inside the factory. Only necessary if you are using the confirmable module
   sign_in user
 end
end
6. In spec_helper.rb add the devise helpers:
RSpec.configure do |config|
 ...
 config.include Devise::TestHelpers, :type => :controller
 config.include ControllerMacros, :type => :controller
 ...
end
7. In your controller spec, now you can do this:
 
   context 'User is logged in' do
    before do
      login_user
    end

    it 'should render index page' do
      get :index

      response.should be_success
    end
  end
 

Make sure that `gem install therubyracer -v '0.11.0'` succeeds before bundling.

1. brew install v8
2. bundle update

How to Create DNS Records using Linode API

dns = Fog::DNS.new(provider: 'linode',
                                    linode_api_key: 'your-linode-api-key-goes-here')
zone = dns.zones.create(domain: 'your-domain.com',
                 email: 'admin@your-domain.com')
zone.nameservers

Create a www version of your site and point to the right IP.
record = zone.records.create(value:  '1.2.3.4', name: 'your-domain.com', type: 'A')

To make www.your-domain.com go to the same place, use a cname record:
record = zone.records.create(value: 'your-domain.com', name: 'www', type: 'CNAME')

to_yaml method y broken in Ruby 1.9

vi ~/.irbrc
YAML::ENGINE.yamler = 'syck'
Save. Now you will be able to use the method y to dump objects in yaml format.

error: The following untracked working tree files would be overwritten by merge: Library/Formula/pbrt.rb

cd /usr/local
git reset --hard origin/master
brew update

Rails 3.2 Tagged Logging

MyLogger = ActiveSupport::BufferedLogger.new(Rails.root.join('log/my_tagged.log'))
MyTaggedLogger.tagged("PAY") { MyTaggedLogger.info "Hello I am working!" }

NoMethodError: undefined method `y' for main:Object

Rails 3.2.6 and Ruby 1.9.3 gives that error. Resolution: YAML::ENGINE.yamler = 'syck'

How to check how long a process has been running

ps -p 64622 -o etime=

PID is 64622
Format is as follows:
16-19:18:35
DD-HH:MM:SS

How to install local gem

1. Download the .gem file.
2. gem unpack file.gem .
. is the current directory
3. Specify in Gemfile:
   gem 'name-of-gem', '0.1.0', :path => "/path/to/the/unpacked/gem/directory"
4. bundle install

Turn off generating css.sass and js.coffee files

config.generators.stylesheets = false
config.generators.javascripts = false

in application.rb

Install Ruby 2.0 Preview 1 on Mac OS

$ brew install libyaml
$ rvm install ruby-2.0.0-preview1 --with-openssl-dir=$HOME/.rvm/usr --verify-downloads 1

Install a specific version of gems from a list of gems in a file

cat gems.txt | while read x; do rvm use @@global && gem install $x -v=2.3.8 ; done

find current time mysql

SELECT CURTIME();

Rails Error: Unable to access log file. Please ensure that

log/development.log exists and is chmod 0666. The log level has been raised to WARN and the output directed to STDERR until the problem is fixed.

Resolution: 

Change the line : config.log_level = Logger::INFO

    to : config.log_level = :info

in development.rb, production.rb etc.

List Just Directories Using ls in Unix

ls -ld */

constant ActiveSupport::Dependencies::Mutex (NameError)

Problem:
.rvm/gems/ruby-1.8.7-p299@global/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:55: uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)

Ruby gems version 1.8.14

Resolution:

Downgrade gems. gem update --system 1.5.3

The following SSH command responded with a non-zero exit status.

Problem:

The following SSH command responded with a non-zero exit status.
Vagrant assumes that this means the command failed!

mount -t vboxsf -o uid=`id -u vagrant`,gid=`id -g vagrant` v-root /vagrant

Resolution:

1. On your Mac:
$ vagrant gem install vagrant-vbguest
Since I installed Vagrant as a package (dmg) otherwise do : gem install vagrant-vbguest
2. vagrant up

The gem will automatically install the update. If VM is already running just do : vagrant halt

Reference:

Automatically download and install VirtualBox guest additions in Vagrant

Move to the end of the file in vi

$ then A

Upgrading GIT on Ubuntu 10.04

• sudo add-apt-repository ppa:git-core/ppa
• sudo apt-get update
• sudo apt-get install git

Notes from stackoverflow. This works.

Testing Cookies

Notes from Rails Cookbook:

To fully test cookies, you need to test that your application is not only setting the cookies, but also correctly reading them when passed in with a request. To do that create Cookie object and add that to the simulated test Request object, which is setup before every test in the setup method.

Rails cookie tests : https://github.com/rails/rails/blob/master/actionpack/test/dispatch/cookies_test.rb

Securing Your Server by Closing Unnecessary Ports

I am getting rid of Rails Cookbook dead tree copy I bought in 2007. Notes that are valid for any Rails version.

$ netstat -an

will list all network daemons and the ports they are listening on. This will not show you the service name. To find out do:

$ less /etc/services

This will list the service name and the port number it is running. Diable the service based on your Linux flavor and reboot server to make sure it does not get restarted automatically on reboot.

Debugging Rails Applications

Notes from Rails Cookbook. Since the book is based on Rails 1.2 only some of the recipes are still applicable to Rails 3.2.

1. Ruby syntax checker:
     $ ruby -cw test.rb
        w - warn about questionable code
        c - check syntax

       In vim you can check the syntax quickly while editing by doing:
        :w !ruby -cw

2.  Dump environment info in views:
     <%= debug(headers) %>
     <%= debug(params) %>
     <%= debug(request) %>
     <%= debug(response) %>
     <%= debug(session) %>
     <%= debug(request.env) %>

3. Use rails any_object.to_yaml in your controller's action method.

4. Filter development logs:
    logger.warn "### something went wrong: #{obj.inspect}"

    Show only messages beginning with ### :
    $ tail -f log/development.log | grep "^###"

   This tip combined with Tagged logging feature in Rails 3.2 is powerful debugging tool.

5. Use Firebug console tab to inspect the client server interaction when making AJAX calls.

6. Use Live HTTP Headers to inspect HTTP traffic.

Solving Programming Problems

1. Write down your question.
       This makes you think and clarify your thoughts.
2. Design an experiment to answer that question.
       Keep the variables to a minimum so that you can solve the problem easily.
3. Run the experiment to learn.

Eliminating if else statement using Blocks in Ruby

def foo(a)
  if a == 1
    yield
  else
    42
  end
end

The above method customizes by using a block like this:

result = foo(1) do
  98
end

p result

How to stop continuous running fan in MacBook Pro

My MacBook Pro with 8 GB 1067 MHz DDR3 RAM and 3.06 GHz Intel Core 2 Duo was running the fan continuously for couple of weeks. To fix it, I ran:

$ top

in the terminal. I found two ruby processes had been running for 160 hours continuously and were taking up 93% of the CPU usage. I killed them by doing:

$ kill -9 [process-id]

As soon as those two stray processes were killed, laptop became quiet again.

How to install tmux 1.6 on Mac OS

I was having difficulty installing the version 1.6, the older 1.4 version was being picked up. The fix:

1. /opt/bin should be in the path. You can append this to your path by editing the ~/.profile file. Mine looks like this:

##

# Your previous /Users/bparanj/.profile file was backed up as /Users/bparanj/.profile.macports-saved_2010-06-07_at_22:52:52

##

# MacPorts Installer addition on 2010-06-07_at_22:52:52: adding an appropriate PATH variable for use with MacPorts.

export PATH=/opt/local/bin:/opt/local/sbin:/opt/bin:$PATH

# Finished adapting your PATH environment variable for use with MacPorts.

export PATH="/usr/local/bin:/usr/local/sbin:/usr/local/mysql/bin:$PATH"

2. curl -OL http://downloads.sourceforge.net/project/levent/libevent/libevent-2.0/libevent-2.0.19-stable.tar.gz

3. tar xzf libevent-2.0.19-stable.tar.gz

4. cd libevent-2.0.19-stable

5. ./configure --prefix=/opt

6. make

7. sudo make install

8. tar xzf tmux-1.6

9. cd tmux-1.6

10. LDFLAGS="-L/opt/lib" CPPFLAGS="-I/opt/include" LIBS="-lresolv" ./configure --prefix=/opt

11. make && sudo make install

12 which tmux 

showed that the older 1.4 version was being picked up from /opt/local/bin, I deleted it by : sudo rm /opt/local/bin/tmux

How to check tmux version

$ tmux -V

Rails 3.2 Errno::EACCES Permission Denied when uploading files

1. Make sure the directory has the right permission:

   chmod -R 777 uploads

2. The uploads directory is at the same level as app directory. You can change the upload location from the public folder to any folder by customizing the store_dir in your uploader class:


 def store_dir
     "#{Rails.root}/uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

3. You also have to define cache_dir in your uploader class, otherwise it will still throw exception.


  def cache_dir
    "#{Rails.root}/tmp/uploads/cache/#{model.id}"
  end

Error: This transaction cannot be processed due to an invalid merchant configuration.

ActiveMerchant 1.26, Rails 3.2

Resolution:


1. Create your selling test account using the Preconfigured option.
2. Under Account Type, select Website Payments Pro.
3. My Account --> Profile --> API access to get API username, API Password and Signature

Remember the API credentials are different from the test login account. You have to save the login password to the Sandbox account in Step 1 above. There is no way to go back and view the login password to the Sandbox account.

remove github prompt when checkin

Change the url that has https to :


url = git@github.com:your_github_username/your_project.git